On 07/05/2016 10:46 AM, Artur Safin wrote:
I am working on solving a Helmholtz-type problem, where I am using the
PML method to simulate absorbing boundary conditions. Originally (before
adding PML) I was using the complex GAMG preconditioner from the PETSc
package, which was working fine. But now I am having a difficulty where
the solver does not converge due to PML.
If anyone has any suggestions or experience, that would be greatly
appreciated.
Artur -- there are two options: either the matrix is not invertible, or
the preconditioner is not a good preconditioner for the matrix. My first
step in debugging such problems is usually to try a direct solver such
as SparseDirectUMFPACK first, in order to make sure the matrix is really
invertible and yields the correct solution. Once I'm sure of that, one
can start thinking of the preconditioner.
Best
W.
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Wolfgang Bangerth email: bange...@math.tamu.edu
www: http://www.math.tamu.edu/~bangerth/
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